Compressor



M y 5, 15553 L. M. KROUSE ETAL 2,537,483

. COMPRESSOR Filed June 15, 1946 3 Sheets-Sheet 2 ATTORNEYS May 5, 1953 L. M. KROUSE ETAL COMPRESSOR Filed June 13, 1946 INVENTORS Aee M Armse, Jess A. A/ourse.

W M w R m U Patented May 5, 1953 COMPRESSOR Lee M. Krouse, Kenmore, N. Y., Jess H. Nonrse, Fort Erie, Ontario, Canada, and Helmut It. Katzmann and Fred A. Howard, Buffalo, N. Y., assignors to Fredric Flader, 1110., Buffalo, N. Y.

Application June 13, 1946, Serial No. 676,416

Claims.

This invention relates to the fluid impelling and/or fluid impelled art and particularly to a rotor construction and the mounting of the blades thereon. In the turbine field especially wherein are encountered severe strains and stresses incidental to high rotative speeds, the prior rotor structures have been quite heavy and cumbersome.

The primary object of the present invention is to provide a light weight rotor of practical and durable construction, and one that may be produced economically and maintained in repair most readily.

An equally important object of this invention is to provide the lightest possible construction for the moving-blade carrying members by securing the most eflicient usage of the material contained therein.

The invention further has for its object to provide a novelly fabricated structure of simple design which will satisfactorily withstand or accommodate the axial thrust placed upon the rotor by the air impelling blades thereof and effectively transmit the driving torque during operation.

It is well known that atdisk can be made the lightest possible structure to resist a given radial loading due to blades attached to its periphery when the combination is rotated at high speeds. It is also well known that a tubular shell can be made the lightest possible structure to resist lateral bending due to loads transverse to its axis. Such transverse rigidity is required in a rotor to minimize undesirable vibrations of the rotor and in particular to'avoid instability conditions by raising the critical speed of the rotor above the normal operatingrange. Further, it is well known that disks and shells, particularly when the thickness of such structure is reduced to the minimum necessary for resistance to rupture alone, are liable to instability and vibratory conditions which may impair their ability to carry the blades in a chosen path and/or may materially shorten the life of these structures.

It is also well known that a centrally-holed disk may be made lighter for a given loading if splines orother discontinuities which act as stress-raisers at the central hole periphery are avoided. Provision for transmitting the tangential loadings on the blades to the rotor shaft may then be made by means of friction between members fixed to the shaft and clamped to the disk and the diskitself. I-Iithertofore such frictional contact surfaces have not been disposed so as to aid the disk in resisting centrifugal forces.

It has also been the practice heretofore to utilize the separate advantages, and to counteract the disadvantages, of the other by combining blade carrying disks with a tubular shell structure. carrying ability of the disks and the transverse The resulting structure has the blade- 2 rigidity of the shell while the instabilities of the thin disks and shell are avoided by their mutual reinforcements. Such combination has been made, however, either by means whereby the structural efficiency of the members has been impaired by stress raisers or by making the shell diameter less than the diameter of the disks or else by welding together rimmed disks in which the wide rims form part of the final shell. This last means of assemblage has disadvantages in limitation on materials used, in the special techniques and in the weight of material in preparation of the parts required for manufacture, and in the difiiculty of maintaining in repair, as well as other difficulties attendant on assemblage of theblades to the structure.

Another disadvantage that such composite structures have heretofore suffered under is the diaphragm vibration of the disks which are only secured at their rims and are free to vibrate normal to their plane elsewhere. Still another disadvantage. of such composite structures hithertofore has been the massiveness of the disks at either end of the rotor required to transmit the transverse bending moments from the shell to the stub shafts projecting from the rotor.

One phase of the invention resides in the anchorage of the blades to a plurality of axially spaced disksthrough a shell encircling the disks, in such a manner as to clamp the shell to the disks and bind blades, disks and shell into a unitary Whole.

Further, the invention resides in the manner of clamping the disks together on a hub to ensure greater rigidity of the disks and/ or to frictionally transmit the tangential forces from the blades to the hub, which clamping action may be effected by means which will assist the disks in resisting centrifugal forces.

Again, the invention will be found to reside in structural features which enable a firm anchorage'forthe blades of the rotor.

The invention "will be comprehended more readily from the following description, reference being had to the accompanying drawings, wherein:

Fig. 1 is a fragmentary longitudinal section through the upper half of the improved compressor constructed in accordance with the present invention;

Fig. 2 is a cross sectional view through the rotor depicting more clearly the construction designed for resisting the axial thrust thereon incidental to its operation;

Fig. 3 is a detailed sectional view through one set of the interlocking strain resisting ribs;

Fig. 4 shows a modified securement for the rotor body forming disks;

Fig. 5 depicts a further modified mounting for the disks;

Fig. 6 is a fragmentary view in longitudinal section depicting a modified compressor construction; and

Figs. 7, 8 and 9 illustrate modified modes of anchoring the rotor blades in place.

Referring more particularly to the drawings, the numeral l designates the stator of the improved compressor and 2 the rotor, the latter being fixedly carried by a shaft 3 which has journal support in the bearings l and of the stator end frames 5 and respectively. In the forward end frame 8 of the stator is an annular air receiving opening 8 in which are arranged the guide vanes 9 that serve to direct the ill-- flowing air the rotor blades ill for most effectively moving the air. Within the air delivery opening ll of the aft end frame l are arranged the guide vanes which may serve to direct the hi h pressure discharge into the usual combustion chamber (not shown) of'the well known gas turbine system. The rotor blades It extend radially from the eriphery of the main rotor disposed in rows thereabout in alternation h rows of fixed blades on the stator iii. The stator blades may be made adjustable as well as replaceable by equipping thn individually with circular hubs and mounting shanks ll threaded to receive the clamp nuts ill. By thus mounting the stator blades E l they may readily be assembled on the stator shell and adjusted for their most efiicient performance.

For lightness, the rotor body is made with an, outer shell is and a supporting framework of disks. The number of body r'isks employed will depend upon the length of the drum-like rotor, and the end disks 2t, 2t and 22 will. preferably be heavier than the intermediate disks 23. The several disks are spaced apart on the rotor shaft 3 by spacing collars t l which form therewith a composite hub and al o serve to anchor the disks to the shaft when axial clamping pressure is rought to bear upon the assembly by the clamp nuts 25 and 226. For this purpose the hub-forming portions of the disks may bereinforced and shaped to provide a wedging embrace, as depicted at El. Likewise, the spacing collars may have cooperating cam faces, as shown at 28 in 4 wherein ring-shaped wedges 29 are utilized to anchor the heavier end disks on the shaft. Or, the hub-forming portions of the disks may be extended, as shown at 3B in Fig. 5, toconstitute the desired spacing medium thereby eliminate the necessity of the separate spacers. In lieu of the wedge rings 25, the preferred embodiment of Fi 1 employs a relatively heavy torque ring 3| which is splined on the shaft at 32 and has radial fingers interengagingly straddling lugs fi l on the end disk it.

The rotor construction just described is light in weight and readily iabicated. The several disks may attenuate radially toward their peripheries and be attached thereat to the shell. This is accomplished herein by having the blades anchored directly to the disks, and for this purpose the shell is formed with a peripheral series of holes iii in the plane of each disk. Through these holes extend the anchoring stems 35 of the blades if: for being secured to the disks. Ihe blades seat upon the shell to form an interlock therewith which, when they are anchored to the disk, will bind the shell and the disks into a rigid unit. If desired, the rotor blades may have divided shanks 35 for straddling the peripheral edges of the disks for securement thereto by suitable anchor fasteners, such as rivets 36, a means of securernent between the disks and the shell. The broadened bases is of the blades seat in relila in the shell for lying flush with its outer surface and to afford support against angular displacement.

For reinforcing the rotor structure against axial thrust, two or more of the may be united rigidly to preclude relative lateral motion therebetween. To this end, the heavier *lisks 2i and are provided on their adjacent faces with radial ribs each rib of one disk overlappi a companion one of the other disk and :c. g secured to such companion rib ranged in a manner to iacil' the rotor.

In one end fra'zne having its inner o.

:. sealing rings mounted in sealing ring arse-carries. "ace l being secured by the bea cap K The divided 35, Fig. be spot welded to the disk as an alternative mode of blade attachine t, this being conveniently acbed by t e cooperating electrodes ll and at. Or the disks 4 5 may have a broad rim 49', 7, formed with inclined seats in which the ades 59 have their roots or shanks placed in a manner to lie flush with the side faces of the rim. Thus, spaced parts on the disk s raddle the blade shanks. l'he blade attachment is rendered secure by anchor fasteners in the of wire rings 55 which fit in lateral annular grooves or seats 52 in the o'eposite side faces of the rim and the flush portions of the blade shanks. his simplified mode of blade attachment transmits the blade loads to the disks by double shear on the wire rings at both the ng blade edges. The anchor ri--gs will be retained in place by suitable means such as by peening or rolling the outer edges of the grooves (not shown).

The shell of the drum may be of solid sheet formation, as illustrated in Fig. l, or may be composed of a series of ring shaped sections 53 having their offset to nest in or telescopically lit the marginal portions of the adjoining sections, shown in Fig. 6. By making the drum sections of progressively increased diameters the rotor will take on the form of a flaring b: Preferably, the several sections will be see d together by the de mounting shanks J. their thread enga ing nuts 59 which latter serve to unite the drum, blades and disks 51 into one rigid rotor structure. The

s all extend inwardly through Li h Or, the shell of the drum may be effectively fabricated by interposing rings 54' between the rims 49 of the adjacent disks 49, and suspending such rings from the stator housing by means of the stator blades I4. The rings close the spaces intervening the rims 49 and cooperate therewith in forming a cylindrical shell upon which the rotor blades 69 operate. The closure rings 54 may be considered as constituting the inner shell of the compressor through which the disk carried rotor blades 50 extend. As an alternative construction, depicted in Fig. 9, the shell may be composed of rings 58 overlapping one another at their margins and having such overlapping margins formed with apertures through which the enlarged shanks 53b of the blades 50a extend for anchorage by the rings 5|, all in a manner similar to the disclosure of Fig. 7.

In lieu of the special reinforcement 23?, 38, the rotor disks 97, Fig. 6, may be more substantial and, if desired, with a reduction in thickness in the larger disks. The smaller but more rigid disks 57a may have enlarged hubs 60 splined to the shaft 6| for better withstanding the torque strains as well as the axial stresses. The lighter but larger disks 91b at the opposite end of the rotor also may be interlocked to the shaft by the feathers 92. Therefore, when the rotor hub components are compressed by the clamp nuts,

similar to nuts 26, they cooperate with the tapered rings and hub surfaces 21 and effectively stretch the shaft 6| so that the latter will act as a loaded spring, or tie member, thereby transmitting torque through the friction on the surfaces 27' and relieving the splines of any sudden shock or intermittent vibratory loads. The rotor will therefore be rigid in structure and firmly fixed to the shaft.

The compressor is light in weight but nevertheless durable in construction by reason of the tie-in connections between the component parts which make up the rotor. The drum shell is relieved of the full load of the blades but is nevertheless interlocked to the disks thereby. The torque strains are transmitted in a practical manner to the rotor disks while the latter are designed to successfully resist the axial thrust. While the foregoing description has dwelt largely upon the disclosure as being applicable to the axial flow compressor, the invention is capable of use in other types of fluid fiow machines where a light weight high speed rotor is desired, such as turbines, fluid motors and pumps, all being comprehended in the term compressor.

The foregoing description has been given for ease in understanding the invention and without any thought of limiting its scope beyond that defined in the appended claims, since the inventive principles are capable of assuming other physical embodiments without departing from the spirit of the invention set forth.

What is claimed is:

1. A stator element and a rotor element, one of said elements comprising a tubular body composed of ring-like sections each having its opposite margins telescopically fitting the margins of adjacent sections, and blades carried by said body and having anchoring shanks extending through openings in the overlapped margins for securing the sections against axial displacement.

2. A rotor comprising a shell composed of a plurality of ring-like sections having marginal )wrtions interfitting one another in a telescopic manner, a plurality of axially spaced disks arranged within the shell and supporting the same at the interfitting margins, and blades carried by the shell and having shank parts extending through and close fitting to openings in the interfitting margins and anchored to the underlying disks.

3. A rotor comprising axially spaced disks each having an annular series of pockets adjacent its margin thereabout, an enclosing shell supported by the disks, the shell and disks having registering holes opening into the pockets, blades seating on the shell and having shanks extending through the holes and into the pockets, and means in the pockets engaging the shanks to secure the blades and shell to the disks.

4. A rotor comprising a series of axially spaced disks each relatively thin and flexible in an axial direction and enclosed by overlapping margins of two cooperating rings forming a portion of an outer shell, a fluid impelling blade having as an integral part a base and a depending shank, the base being recessed within one of the cooperating rings to form a smooth exterior surface for the shell, and the blade shank extending radially inwards through the overlapping margins of the cooperating rings of the shell and into a recess in the margin of the disk, and a fastener attached to each blade shank and acting to align the cooperating rings of. the shell and said fasteners acting radially to tension the thin flexible disks and thereby render the structure resistant to all operational loads.

5. A rotor comprising a shaft, a plurality of axially spaced relatively thin flexible disks on the shaft, an encircling shell enclosing the disks, and fluid impelling blades, a torque transmission means consisting of splines between one or more of the disks and the shaft, means for centering and compressing the disks against conical rings on the shaft, said blades having depending shanks which extend radially inward from the outer surface of the shell and through rim portions of the disks, the shanks being secured by fastening means recessed into holes through the disks, the shaft together with the conical ring tightening means and the blade shanks as well as such fastening means serving to align the entire structure and make it resistant to all operational loads and stresses.

LEE M. KROUSE.

JESS I-I. NOURSE. HELMUT R. KATZMANN. FRED A. HOWARD.

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